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How does glucose become ATP through cellular respiration?
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mitochondrion
Mitochondria (red) are found throughout the cytoplasm of almost all eukaryotic cells (cell nucleus is shown in blue; cytoskeleton is shown in yellow).
Cellular respiration converts glucose into ATP through three primary metabolic stages:
- Glycolysis: Occurring in the cell, this 10-step process breaks down one glucose molecule into two molecules of pyruvate. This stage yields a net gain of two ATP molecules and produces NADH.12
- Tricarboxylic Acid (TCA) Cycle: Pyruvate enters the mitochondria and is converted into acetyl coenzyme A, which enters the TCA cycle. This cycle produces additional ATP and reduces NAD+ and FAD into NADH and FADH2, which carry high-energy electrons to the final stage.13
- Oxidative Phosphorylation: Located in the mitochondrial cristae, the electron transport chain uses electrons from NADH and FADH2 to pump protons across the inner membrane. This creates an electrochemical gradient. As protons flow back into the matrix through the F1F0ATPase complex, the released energy is used to synthesize large amounts of ATP.14
Ultimately, oxygen acts as the final electron acceptor, combining with protons to form water.14